Speedometer



March 1, 1932. R O, HELGEBY 1,848,061

SPEEDOMETER Filed May 24, 1928 Patented Mar. 1, 1.932

UNITED STATES PATENT OFFICE HALI'H o. HmGHBY, or rLINT, MICHIGAN, AssIGNon To A C srAnH PLUG COMPANY, or

' rLINT, MICHIGAN, A ConronAI-ICN or MICHIGAN SPEEDOMETEB Application tiled lay 24, 1928. Serial No. 280,261.

This invention relates to measuring instruments and harshbeen designed more particularly as an improvement in speedometers for use'on vehicles. l

An object of the invention is to improve the mechanism by which the movable members of the two parts of such an instrumentthe s d indicator .and the odometer-are both riven. More specifically, it is an object of the invention to utilize a flexible drive cable, having its end within the instrument and directly driving the rotor shaft. As a further object, the invention gives the desired angle of approach to theiiexible drive 5 shaft, providing maximum'clearance in installation. Another object is to avoid short lengths of shafting between the rotor shaft of the instrument and the conventional flexible shaft. Other objects and advantages will be o understood from a reading of the vfollowing description, and an examination of the accompanying drawings.

In the drawings:

Figure 1 is a vertical section through the instrument with partsin elevation and parts broken away.

Figure 2 is a. section on line 2--2 of Figure 1.

Figure 3 is a side elevation showing the main frame which supports the mechanism.

The instrument is of the type known as a magnetic speedometer and consists of a mechanically operated mileage recording odometer and a magnetically controlled speed indicating mechanism. Both are drlven directly and simultaneously by a single flexible speedometer cable.

. The combined instrument is housed in a casing 9. Within casing 9 is a main supporting rame 10. This frame is preferably formed by die casting and is held 1n position in the casing by means of a mounting plate 11 which is. in a suitable way not shown, secured to the frame 10 and removably attached to the casing.

The rotor shaft is journalled in a vertical bore of the die cast supporting frame 10 and is, itself, suitably bored and broached to re ceive a s uare terminal head 26 carried by the inner en of the flexible shaft 27. The lower `wardly.

end of the rotor shaft is ared to guide the terminal head 26 of shaft 27 in a manner which will be obvious from an inspection of Figure 1.

The driven member consists of the flexible cable 27 which is driven at one end by a suitable speedometer drivelgear, not shown. At the instrument endthacable 27 enters and directly drives the rotor 25. The arrangement by which such a cable is operatively connected to the instrument to drive the combined units constitutes the principal subject matter of the present application.` This ar-` rangementv will now be described in detail.

A non-circular, preferably square, driving head 26 is fixed to the inner end of cable 27. This head is designed to be slidabl but nonrotatably mounted in a similarl'y shaped opening in the rotor shaft 25. The casing 9 is shaped at its rear wall, as shown in Figure 1, so that the cable leaving the instrument at right angles to said wall is directed away from the instrument board. It should be noted that the axis of the rotor shaft is verti!l cal 'and angularly related to the casing wall referred to. This arrangement is accommodated by giving the end of the cable, the part within the casing, a slight angle or bend back- A cable retainer 46 is fixedly mounted on the cable below the bend, to which reference has been made. The retainer 46 has a flanged head 47 which is to engage a shoulder 48 in the bore of a coupling or ferrule 49. As clearly shown in Figure 1, the retainer 46 is elongated and is rotatable within a bearing bore of the ferrule 49. The engagement of parts 47 and 48 retain the free end of cable 27 in proper relation with the rotor shaft 25, giving a smooth running condition and eliminating an tendency to cable whip in the angular drive between the ferrule bearing and the rotor shaft. The housing 56 for the ficxible cable 27 terminates within and is secured to the outer end of coupling 4 9.

A clamping member is secured in any suitable manner to the errule 49. Preferably, the errule has an annular flange 49 engaging the casing wall and the clamp 50 is secured to the coupling or ferrule just outside the Bange. The clamp extends along but out of contact with the casing Wall, being inwardly bent and engaging the wall at its end. The end of the clamp is biturcated forming a U-shaped slot 51, as at Figure 2. A screw-threaded bolt 52 suitably secured to the casing extends between the furcations of the slot and a fastening nut^ 53` may be threaded on the bolt and engage the clamp to secure it in position and thereby hold the ferrule 49 irmly in position.

The frame is provided w directed guide ears 54 cast thereonandlocated on either side of and below the opening into the rotor shaft, so that when the cable is directed into the opening in casing 9 the drive head 26` will be guided into engagement with shaft Q5. Sincethe clamp 50 is secured to the errule 49 and Aalso to the cable housing 56, a quick and easy-yet positiveconnectiou can be made which is tightly held in place by nut 53.

y In some' earlier arrangements, the need vof the bendin the cable has been recognized and such b entportions were located outside of and b elow'the instrument.- By'this arrangement,the bend awayfrom the vertical l'frel(inently brought the cable objectionably low 'and in the way'o the knees ofthe occupants or'the `operating` levers. In 'such rarrangements, too.fthe clamp was not secured -to the ferrule. By Athe present improvement, the bent prtion 'of the cable is within the instrument and thel cable is ffre'e' from any sharp bends out-side the instrument.v `This avoids the diliicult'ies mentioned. Furthermore, the' clamp is secured tothe ferrulewhereby theattachmentis simplified. The 'cable leavesthe instrument at a desired angle to give the maximum clearance and an easil ith downwardly said rotor shaft, said flexible shaft being curved from its position of engagement with said rotor shaft and extendinv through said wall in a direction substantially at right angles thereto, said flexible shaft being extended outside said casing.ffrom said wall whereby it maybe connected to a source of drive.

2. The invention defined by claim 1, a ferrule secured`to'said wall, a sleeve fixed to' said ilexible shaft and rotatably mounted in said errule.

RALPH O. HELGEBY.

attached andrigid arrangement is provide The drive headl 26 floats freely in the rotor shaft, preventing any possible binding'ir cable whip and,"a feature which is of much importance, the drive is taken directly from the main speedometer cable 'which is in one length, eliminating vtheshort length of wire cable such as has frequently been used in the past. The errule 49 is ofjsimpler design and, therefore, lcheaper to manufacture than the parts corresponding thereto in prior constructions. A

The invention 'described above yin detail relates to the driving means forthe mechanisms of the combined speedometer and-odometer.

It is not concerned with thel specific details of these mechanisms themselv`es.` Forthat reason more detailed' descriptive matter of these mechanisms is omitted.

I claim: l

1. In a measuring instrument, a rotor shaft therein, an enclosing casing for said instrument, said casing having a wall in a plane at an acute angle with the axis of said rotor shaft, a` flexible drive shaft having one end in removable but driving engagement with lll 

